Sources of economic growth for SpaceX, reusable rockets

[sghill]

But most of the volume. Fiberglass has very low density. That makes the requirement for the structure which is most of the mass. Electronics get smaller and System on a Chip (SoC) designs start reducing the volume.

Edit: Or actually, more likely is that satellites stay fixed size and get more capable because the marginal cost of X more fuel isn't much once you have the launch of an ELV. We need some cheap microsat/nanosat launchers.

again, it isn't the electronics.  Microsats and nanosats can't be comsats.  The comm package where the mass is.   The difference between a laptop and smartphone in terms of electronics would have little effect on the mass or size of a comsat.

Well then Jim, looks like we should all just agree to disagree on this point.  We'll come back in ten years and see who's argument was closer to the reality we see then.   

Jim's right.  The signal processing electronics could fit on a dime, but the power handling and amps are where the weight is.  I've worked in radios since the 90's- including satellite TV ground stations and cellular communications- and I've seen very little change to the amps and transceiver equipment even as the equipment racks for handling the traffic have gone from room sized to a single rack.

[watermod]

One of the great mistakes in Iridium was to use movable antennas to talk to the neighboring Iridium sats.   The movements changed balance and orbits of the satellites which caused the use of lots of extra fuel to maintain the proper orbit.  If they had used phased array antennas to do electronic beam forming instead of moving a physical antenna they would not have used as much fuel to keep their orbit.  Over the life of an LEO Iridium sat it could have been a big deal on the mass end of things.   So, yeah, modern electronics can make a big difference in the required size.

1.  How does spacecraft mass properties affect the orbit?

2.  Phased array antennas would require more power and hence larger solar arrays

1.  How does spacecraft mass properties affect the orbit?
The constant movement of the antennas so they could talk to the neighboring sats in the constellation were causing orbit and stability changes.  To compensate, at one point, they had rooms full of engineers flying the sats.   All those adjustment used up fuel mass at a much higher than planned rate.

2.  Phased array antennas would require more power and hence larger solar arrays
Maybe and maybe not,  but definitely less fuel consumed to remain in orbit.  I'll send you a patent I got beat to the patent office on (slow lawyers) if you want detail.   We looked into phased arrays for cellphones - both towers and the phones to do a feedback of phase in buildings or city canyons in much the same way that power control does.  After some test by a group in Israel we gave up on it for city canyons.   These big moving reflectors called semi-trucks destroyed the outside feedback scheme.  It still worked fine in building where you had metal 2x4s etc.    As I was more concerned with the phase strength I didn't bother with the power control logs.

Oh, I and several others, discussed this in great detail (unofficially) with  the same designer/manager after he left Iridium development and  who was later named in the Iridium Supreme Court case.  (Supremes found him responsible so he  jumped ship to a defense contractor)

[ArbitraryConstant]

So either we are going to see LEO constellations or most of the communication will become terrestrial again with cables as backbones.

It's been overwhelmingly terrestrial all along. I think the overall impact of that is to add demand for satellite broadband, not reduce it, because densely populated areas support applications that everyone else then wants access to.

The question for me is how much of the demand is going to go to solar powered drones rather than LEO satellites, as that will suck a lot of value out terrestrial broadband applications that satellites might hope to take advantage of. Presumably a good deal of the amortization of a LEO satellite would come from, say, rural Arizona, rather than, say, the average patch of open ocean, even if the ocean revenue isn't strictly zero (which it wouldn't be).

So I doubt that in the very long term and assuming the kind of technical evolution you are describing the GEO Comsat market will see such a development towards cheaper, shorter, more.

The GEO evolution seems to be towards more sophisticated antennas that can support smaller and smaller cells, so to an extent you can trade mass in GEO for more aggregate bandwidth. Ultimately you're diffraction limited at wavelengths that reliably make it through the atmosphere, but I don't think we're there yet.

[pippin]

Well, the problem with GEO is not only cell size, it's also latency. It's too much for good IP based communication. It might be acceptable in those rare cases where you have no other means of access but for everything else it won't be competitive.

So what's the use case for GEO comsats in the long run? I just don't see it. Broadcast is going away and terrestrial backbone bandwidth is going to be so high that also the "let's move big chunks of data in batch mode" case is not there. Backbone broadcast for things like distributing live TV streams and things but that, too, will not be worthwhile distributing over sat if it's just a minor volume compared to what your terrestrial infrastructure transports anyway.

I agree that there will be fight between drones and LEO sats for the semi-remote areas, I'd counted drones under "terrestrial".

So what does this leave GEO? I really don't see that as a growth market in 10 or 15 years, it's a segment you want to cash in on today or never.

[ArbitraryConstant]

Well, the problem with GEO is not only cell size, it's also latency. It's too much for good IP based communication. It might be acceptable in those rare cases where you have no other means of access but for everything else it won't be competitive.

You're overstating this. It competes with dialup and the lower tiers of DSL in the real world. The latency is excessive for, say, gaming, but that is demonstrably not prohibitive (demonstrably since it's commercially viable in the real world right now).

So what does this leave GEO? I really don't see that as a growth market in 10 or 15 years, it's a segment you want to cash in on today or never.

You could ask where GEO was left over the last 20 years, but the reality is that improved terrestrial broadband just made it that much more valuable at every step; there's more to connect to.

Terrestrial coverage has improved, but the value to remote areas increased faster.

[RocketGoBoom]

Lag Sucks !!!
http://wiki.answers.com/Q/What_is_the_Round_Trip_time_of_a_RF_signal_for_GEO_satellites

the speed of light = 299792458 m / s

GEO (Geostationary Earth Orbit) = 35863000 m above the Earth's surface

round trip time = 2*(35863000)/299792458 =0.239 s

the time needed for an RF signal to reach a GEO satellite and gets retransmitted back to a ground station on earth is approximately 240 milliseconds

[Elmar Moelzer]

Lag Sucks !!!
http://wiki.answers.com/Q/What_is_the_Round_Trip_time_of_a_RF_signal_for_GEO_satellites

the speed of light = 299792458 m / s

GEO (Geostationary Earth Orbit) = 35863000 m above the Earth's surface

round trip time = 2*(35863000)/299792458 =0.239 s

the time needed for an RF signal to reach a GEO satellite and gets retransmitted back to a ground station on earth is approximately 240 milliseconds

Which is quite a lag for games. It is OK for other uses, though. I agree and think that LEO constellations might be better in the future.

[dlapine]

Lag Sucks !!!
http://wiki.answers.com/Q/What_is_the_Round_Trip_time_of_a_RF_signal_for_GEO_satellites

the speed of light = 299792458 m / s

GEO (Geostationary Earth Orbit) = 35863000 m above the Earth's surface

round trip time = 2*(35863000)/299792458 =0.239 s

the time needed for an RF signal to reach a GEO satellite and gets retransmitted back to a ground station on earth is approximately 240 milliseconds

Which is quite a lag for games. It is OK for other uses, though. I agree and think that LEO constellations might be better in the future.

So a better phrasing would be that a GEO satellite constellation would not be useful for most gaming, phone service or video conferencing, but great for everything else depending on price.

Even video streaming is fine with that lag, if the signal can be kept constant.

The bigger question is whether you can build a constellation cheaply enough to provide competitive internet data service for the areas where the local coverage is poor.

[ArbitraryConstant]

No he is not overstating this.  Satellite lag from GEO precludes most two-way communications except where terrestrial alternatives are not available (or preferable).  This is basically all modern telecommunications except for broadcast and military needs.

Shrug. It's alive and well competing against rural DSL. There's no point arguing about it when we can just look and see people using it, including in the US.

No one is going to invest and build a two-way platform to use in GEO when they can do so at lower orbits or using terrestrial alternatives.

Doing so at lower orbits requires orders of magnitude more satellites, so it doesn't automatically win the trades even at lower launch prices. Depends on overall demand and alternatives. Alternatives even if they aren't full replacements will nevertheless eat up much of the revenue that could be anticipated, and make it harder to justify a big new satellite network.

[AncientU]

Google is experimenting with dirigibles for world-wide data coverage.  Affordable launch costs plus mass-produced satellites seems vastly better than airships.
http://www.telegraph.co.uk/technology/google/10084512/Google-blimps-will-bring-the-web-to-Africa.html

Edit: Added reference and changed question to statement.

[Elmar Moelzer]

Isn't Google experimenting with dirigibles for world-wide data coverage?  Affordable launch costs plus mass-produced satellites seems vastly better than airships.

I agree. If SpaceX can lower launch costs as anticipated, this should make more sense than dirigibles.

[pippin]

It's not just games. Most internet applications are heavily interactive these days and communicate a lot back and forth. Application providers go to great length to have local infrastructure to keep latency around 100ms.
I have used GEO Internet services, even using something like GMail through that will drive you crazy and it had a terrestrial uplink.
You also have to see that these 240ms or so are overly optimistic. That's not taking into account all the latencies in your terrestrial infrastructure (your service is not where the uplink is, all the switching and stuff and so on). Plus you are rarely right at the equator so your average trip times are easily twice as high.
Realistically we talk about half a second and a lot of internet services are not really usable with that. And all of this assumes a terrestrial back channel or the real round trip, going over the sat again gets even longer.

And then if you need a terrestrial network for most applications anyway there is little reason for a secondary channel.

Comsats have been successful in the recent years because satellite TV was but all usage statistics you can see show you that broadcast TV use is already in heavy decline with people under 30 and with on-demand channels becoming more and more available this will increase a lot. I know about Big TV networks already seriously considering to back out of some of their distribution channels.

A big factor is that people don't necessarily stop to watch the TV programs (like series, sports and so on) but they are not watching them through TV broadcast but on-demand or internet channels instead. Once the content providers realize that they'd better not fight his but change their monetization schemes the change will be all the more dramatic.

[Elmar Moelzer]

Agreed, cloud based applications are becoming more common. They need fast internet connections with low lag.
I think that LEO based constellations would be good enough. GEO, I cant see working.

[llanitedave]

No he is not overstating this.  Satellite lag from GEO precludes most two-way communications except where terrestrial alternatives are not available (or preferable).  This is basically all modern telecommunications except for broadcast and military needs.

Shrug. It's alive and well competing against rural DSL. There's no point arguing about it when we can just look and see people using it, including in the US.


The only thing it can really compete against is dialup.  We were using it at home in our very rural area until last year, but we jumped ship as fast as we could when 4G service became available.  It's alive, but I wouldn't call it well.  It's a desperate measure.

[Ludus]

http://www.parabolicarc.com/2014/02/16/google-planning-son-teledesic/

A Teledesic 2.0 sort of project is an example of ambitious new demand that might emerge if spacex is making deals for buys that soak up lots of launches. If launches can be bulk purchased for say $6 million rather than $60 million for falcon 9 performance to LEO, a company with lots of cash and internet ambition might consider a constellation of big powerful satellites for global broadband (that could incidentally also have hi-res cameras and provide total real time photo coverage). Big satellites with lots of PV arrays, lots of power, big antennas, redundant electronics, robust construction, which are produced by the hundreds can be orders of magnitude cheaper per unit. A large high performance satellite with a launch cost of a few million can also be made for a few million. Sort of the Planet labs approach scaled up.

While continuing to sell regular launch services at much higher market prices, projects that buy hundreds of launches could get appropriate pricing. Rapid reusability has the potential to lower marginal costs to make this sort of pricing deal possible, even in a period where ordinary one-off launch prices have not fallen much from current levels. That implies that profit percentages on regular launches could be much higher.

[simonbp]

All of Juno's spacecraft avionics are in this vault. A reduction in the size on the cards inside it would not have an appreciable affect on the spacecraft size.   The mass of a GSO comsat is the payload package (TWTA, receivers, solar arrays and antennas) and the rest of the spacecraft is size to this and not the avionics.

Juno is maybe not the best example, because it has really heavy vault for surviving Jovian radiation. The vault holds both the control system and scientific electronics (i.e. the payload). Smaller cards would have reduced the size and mass of the vault, and therefore the size and mass of the bus. And being an escape mission, there is a much greater benefit to minimizing mass. The overall size of spacecraft was dictated by the very large solar arrays, which again are not typical for GEO sat.

Really though, I could believe that the trends to progressively larger GEO sats and fewer open slots will reach its logical conclusion and commercial satellite operator will move to using large monolithic platforms that could be serviced and refueled robotically.

[Jim]

Juno is maybe not the best example, because it has really heavy vault for surviving Jovian radiation. The vault holds both the control system and scientific electronics (i.e. the payload). Smaller cards would have reduced the size and mass of the vault,

Not by enough to really matter.  A vault half the size wouldn't have changed the spacecraft.  The point was that changes to  the avionics are over shadowed by other systems, propulsion, power production and storage, and communication package of a comsat.

[ArbitraryConstant]

The only thing it can really compete against is dialup.  We were using it at home in our very rural area until last year, but we jumped ship as fast as we could when 4G service became available.

Good call; but it's hard to see a LEO constellation being competitive with an area that can support 4G service.

Cell towers can pick their location. GEO birds can pick their location (somewhat) and choose where they point their antennas. So-called atmospheric satellites will be able to choose where they loiter. But a LEO satellite won't be able to control its ground track. The main issue I'm trying to surface here is that much of the revenue potential for a LEO satellite's ground track will be in areas that are sufficiently densely populated to support a denser communications medium. There are certainly cases that LEO can handle better but it isn't automatically the case that the gap between terrestrial means and GEO will support a huge new satellite constellation.

[Elmar Moelzer]

The only thing it can really compete against is dialup.  We were using it at home in our very rural area until last year, but we jumped ship as fast as we could when 4G service became available.

Good call; but it's hard to see a LEO constellation being competitive with an area that can support 4G service.

Cell towers can pick their location. GEO birds can pick their location (somewhat) and choose where they point their antennas. So-called atmospheric satellites will be able to choose where they loiter. But a LEO satellite won't be able to control its ground track. The main issue I'm trying to surface here is that much of the revenue potential for a LEO satellite's ground track will be in areas that are sufficiently densely populated to support a denser communications medium. There are certainly cases that LEO can handle better but it isn't automatically the case that the gap between terrestrial means and GEO will support a huge new satellite constellation.

What speaks against this is that satellite phones have been picking up in business recently. If they have enough customers, so should internet. The military might also be interested in a high bandwidth communications from anywhere.

[AncientU]

Wouldn't a LEO constellation be able to provide continuous communication between any satellite and the ground and vise versa?  IP for ISS, Bigelow, Dragon?  Once you have full coverage of the planet and the complex control system to hand off traffic, all airliners, ships, trains, buses, cars, trekers, etc. will have wifi (won't that be fun).